The effects of dietary proteins with different rates of digestion and absorption on food intake and subjective feelings of appetite, and circulating blood amino acids in normal-weight young adult men

INTERVENTION: The design of the study is a randomised single‐blind cross‐over design. Each male participant participated in 5 sessions in total with a minimum of at least 2 days between each session. On each study day, participants arrived in the morning after fasting for about 10 hours. Upon arrival at the laboratory (Human Nutrition Research Unit), an intravenous cannula was placed in a vein of the subject's arm to allow for drawing of multiple blood samples. After the initial fasting blood draw (baseline), the subject filled out his first set of Visual Analogue Scales (VAS) questionnaire to assess his feelings of appetite and well‐being. The subject was given his preload meal (enriched tomato soup, plain biscuits and 100 ml of water) to consume within 15 min. Consumption of the preload meal was directly supervised, namely the amount of the preload meal ingested and the time it took to consume all of the preload meal were recorded. After complete ingestion of the preload meal (time 0), a questionnaire for the palatability of the preload meal and a VAS questionnaire is completed. The VAS questionnaire was completed at 30, 60, 90, 120, 150, 180, 240, 300, and 360 min. Blood (10 ml each) was collected at 60, 120, 180, 240, 300, and 360 min. At 120 and 240 min, 250 ml of water was given to the participants to keep them hydrated. After completing the 360 min blood draw and VAS questionnaire, the cannula was removed and subjects were provided with a hot meal and water to consume until satisfied within 15 min. The participant was asked to fill in a questionnaire asking about the overall likeability of the hot meal of fried rice at that time, and a VAS questionnaire 15 and 30 min following complete consumption of the hot meal. The participant was then able to leave the laboratory.